This application claims the benefit, under 35 U.S.C. xc2xa7119, of Danish Patent Application No. PA2000 00095, entitled xe2x80x9cEffects modules and combinations thereof to produce a variety of lighting effects,xe2x80x9d filed Jun. 26, 2000.
The present invention relates to automated lighting systems for use in entertainment, promotional, and architectural applications. Particularly, the invention relates to manipulating a light beam from such projectors to produce lighting effects.
Conventional projectors for stage, theater, architectural, and display illumination include means for removably inserting various types of optical beam modifiers into the path of a light beam to vary the color, intensity, size, shape, and pattern of the beam. Thus, in a typical system, a light source produces white light which is passed, for example, through at least one color filter wheel for producing a colored light beam, a gobo wheel for imposing a selected pattern on the light beam, a light intensity wheel for varying the intensity of the light transmitted therethrough, a mechanical iris for determining beam size, and a lens system for controlling light beam focus and divergence. U.S. Pat. No. 4,392,187 to Bornhorst discloses several such systems.
For imposing a desired pattern on the light beam, it is well known to pass the beam through a gobo, which is a template or light stencil having a predetermined pattern. Typically, gobos are formed by chemically etching the desired pattern onto stainless steel discs. The gobos discs are usually supported in the projected light beam to impose upon the light passing therethrough the pattern which has been etched into the discs. It is well known, for example from U.S. Pat. No. 4,460,943 to Callahan, to provide a mounting plate having a plurality of equally spaced apertures arranged around a common axis for mounting gobos within one or more of the apertures. The plate is drivingly rotatable, such as via a motor, about its axis to insert a selected gobo into the path of the beam of light. U.S. Pat. No. 4,891,738 to Richardson discloses a similar arrangement including an apertured gobo mounting plate which is rotatably driven by motor driven rollers frictionally engaging the peripheral edge of the plate. The gobos are mounted on or within holders which, in turn, are fixedly positioned within the plate apertures. The mounting plate is rotatably driven to position a selected gobo within the beam of light. After reaching this position, a motor-operated holder drive mechanism acts, through frictional contact with the rim of the holder, to rotatably drive the gobo holder in either direction at various speeds. In this manner, the plate is rotatable to position a selected gobo within the beam of light and the gobo holder is rotatable to spin the gobo holder within the beam of light.
Generally, the projectors are constructed in a compact fashion because the rotational inertia of the projector increases the speed at which the beam of light can be moved into position. This compact design leads to various disadvantages in the maintenance and upkeep of the projectors. Furthermore, the compact design of the projectors hinders the replacement of gobos in the projector.
For example, U.S. Pat. No. 5,402,326 to Belliveau discloses a gobo carousel that contains a number of gobo holders. The carousel is rotatable to position a desired gobo within the light path and further includes means for rotating the holders relative to the carousel itself. The holders are permanently attached to the carousel and include a mechanism for securely retaining and for replacing gobos from within the holders. However, due to the compact design of the light projector, such gobo carousels, as well as the gobo holders, are often mounted in close proximity to adjacent mechanical parts. Accordingly, replacing the gobos in the gobo holders can be very awkward. Therefore, there is a need for a system that enables easy exchange of the gobos in such compactly constructed projector.
Another problem related to the compact design of the projector is thermal management. In high intensity versions of such projectors, the interception of the light beam by gobos leads to a build up of heat. If this heat is not sufficiently managed, deterioration and even destruction of the gobos can result. In order to keep the gobo within necessary operating temperature ranges while intercepting the light beam, an appropriate thermal management system should be employed. Therefore, there is a need for a compact system for facilitating the thermal management of the gobos. Additionally, when projecting light onto a subject, it is often desirous to blur the image, which is known as a xe2x80x9cfrost effect.xe2x80x9d The frost effect is typically provided by a pair of opposed flags that partially intercept the beam, the extent thereof providing a variable degree of frost. However, such frost effect systems are difficult to maintain and configure in compact projectors. Therefore, there is a need for a convenient and easily configured system for providing image frost effects.
The present invention provides a system and method for easily replacing gobos in a compact projector by providing rotatable gobo holders that are adapted to be easily removed from and reattached to the permanently mounted gobo carousel. In accordance with one aspect of the invention, a gobo wheel assembly is provided including a rotatable base plate, a gobo holder, a spring retainer adapted to removably couple the gobo holder, and a central sun gear.
There is further provided a gobo cooling system including an air flow and a window positioned within the light path in the projector. The window is positioned within the air flow to deflect air to a gobo.
Additionally, there is provided an effects wheel including a rotatable baseplate and a transparent frost filter forming a portion of the baseplate for creating frost effects.